Proceedings of the National Academy of Sciences,
Journal Year:
2024,
Volume and Issue:
121(51)
Published: Dec. 9, 2024
The
observation
of
mass-independent
sulfur
isotope
fractionations
(S-MIF)
in
Archean-Paleoproterozoic
rocks
has
been
instrumental
constraining
oxygen
levels
on
early
Earth.
S-MIF
effect,
experimentally
demonstrated
to
result
from
photochemical
reactions,
now
observed
coal
combustion,
expanding
our
understanding
this
phenomenon.
Our
study
reveals
that
the
negative
Δ
Geology,
Journal Year:
2024,
Volume and Issue:
52(4), P. 292 - 296
Published: Feb. 7, 2024
Abstract
The
Sturtian
“Snowball
Earth”
glaciation
(ca.
717–661
Ma)
is
regarded
as
the
most
extreme
interval
of
icehouse
climate
in
Earth’s
history.
exact
trigger
and
sustention
mechanisms
for
this
long-lived
global
remain
obscure.
widely
debated
causes
are
silicate
weathering
ca.
718
Ma
Franklin
large
igneous
province
(LIP)
changes
length
degassing
continental
arcs.
A
new
generation
two
independent
Neoproterozoic
full-plate
tectonic
models
now
allows
us
to
quantify
role
tectonics
initiating
sustaining
glaciation.
We
find
that
arc
remains
relatively
constant
from
850
until
end
both
unlikely
play
a
role.
plate
motion
diverge
their
predictions
timing
progression
Rodinia
break-up,
ocean-basin
age,
ocean-basement
depth,
sea-level
evolution,
mid-ocean
ridge
(MOR)
carbon
outflux.
One
model
predicts
MOR
outflux
ocean
basin
volume–driven
sea
level
lower
than
during
Late
Cenozoic
glaciation,
while
other
outgassing
exceeding
those
Cretaceous
hothouse
climate.
second
would
preclude
major
first
implies
could
have
been
combination
an
extremely
low
(~9
Mt
C/yr)
LIP
weathering.
Such
minimal
maintained
state
57
m.y.
when
was
markedly
reduced,
with
gradual
build-up
CO2
atmosphere
paired
terrestrial
volcanism
leading
its
termination.
Minerals,
Journal Year:
2025,
Volume and Issue:
15(4), P. 366 - 366
Published: March 31, 2025
The
interglacial
period
of
the
Cryogenian
glaciation
is
a
pivotal
interval
in
geological
history,
marked
by
two
“Snowball
Earth”
events
and
emergence
early
animals.
Currently,
there
considerable
debate
regarding
paleo-oceanic
environment
dominant
factors
controlling
organic
matter
enrichment.
Here,
based
on
inorganic
geochemical
data
mineral
composition
from
Datangpo
Formation
Xiangtan
(South
China),
combined
with
previous
research,
we
have
analyzed
paleo-climate,
redox
condition,
seawater
restriction,
primary
productivity
across
different
sedimentary
facies
during
this
critical
interval.
results
exhibit
that
can
be
divided
into
three
members
(Da1–Da3)
lithology.
Paleoclimatic
proxies
suggest
was
relatively
cold
deposition
Da-1
Member,
while
it
warm
humid
Da
2–3
members.
Compared
to
shallow
water
areas,
deep-water
areas
experienced
more
rapid
transition
paleotemperature
following
Sturtian
event.
Combining
Mo-U
elements,
CeN/Ce*N,
Corg/P
ratios,
characterized
an
oxic
Formation,
then
gradually
transitioned
suboxic,
finally
anoxic
conditions.
Furthermore,
decompression
terrestrial
magma
chambers
led
intense
volcanic/hydrothermal
activity
deglaciation
period.
Hydrothermal
most
depositional
period,
followed
Da-2,
declined
Da-3
not
only
provided
essential
materials
for
formation
Mn
carbonate
ores
but
also
significantly
enhanced
introducing
large
amounts
nutrients
paleo-ocean.
indicators
(Ni/Al,
Cu/Al)
exhibited
obvious
coupling
CeN/Ce*N
ratios
indicating
oxygen-rich
environments
were
favorable
biological
proliferation,
thereby
providing
abundant
matter.
Anoxic
conditions
further
facilitated
preservation
matter,
which
may
factor
driving
enrichment
Formation.
Geochimica et Cosmochimica Acta,
Journal Year:
2023,
Volume and Issue:
365, P. 114 - 135
Published: Dec. 7, 2023
The
Cryogenian
period
of
the
Neoproterozoic
was
marked
by
two
Snowball
Earth
glaciations
that
bookended
a
non-glacial
interval
lasted
roughly
10
million
years.
break-up
Rodinia
in
early
gave
rise
to
numerous
rift
basins
whose
time-varying
redox
dynamics,
linked
marine
productivity
and
biogeochemical
cycling,
were
likely
controlled
varying
degrees
basin
restriction
response
sea-level
change.
Those
drivers
associated
with
both
global
(Sturtian
deglaciation
possibly
onset
Marinoan)
local
tectonics
(regional
uplift/subsidence).
To
explore
these
relationships,
we
focus
on
Datangpo
Formation,
an
exceptional
shale
sequence
deposited
marginal
South
China.
succession
comprises
lower
organic-rich
black
shales
upper
organic-lean
gray
shales/siltstones.
As
elucidated
our
integrated
data,
former
H2S-rich,
deep-water
settings
underlying
highly
productive
surface
waters.
We
attribute
this
elevated
nutrient
supplies
replenished
from
open
ocean
following
rise,
as
augmented
high
terrestrial
input
phosphate
wake
Sturtian
deglaciation.
By
contrast,
shales/siltstones
relatively
shallow
deposition
oxic/suboxic
water
column
suppressed
primary
production.
major
driver
dramatic
shift
chemistry
may
lie
greater
extent
isolation
corresponding
reduction
fluxes
due
significant
fall—possibly
regional
uplift.
At
time,
experienced
influx
detrital
clays
organic
material,
perhaps
triggered
sea
level.
Surprisingly,
found
euxinic
conditions
prevailed
for
substantial
more
isolated
conditions.
This
relationship
can
be
attributed
redox-dependent
phosphorus
cycling.
Specifically,
H2S-replete
facilitated
regeneration
bioavailable
phosphorus,
initiating
positive
feedback
allowed
persistence
anoxic
study
advances
understanding
cycling
evolution
during
under
influence
large-scale
fluctuations
connectivity
must
have
been
common
many
at
time.
Furthermore,
sheds
novel
light
iron
proxy
sulfur
Almost
all
silicate-bound
converted
into
reactive
phases
strong
chemical
weathering,
while
data
revealed
isotopic
stratification
deglaciation,
important
messages
interpretations
analogous
aftermath
other
climate
upheavals
history.
